前言：鉈-201心肌灌注掃描一般採用仰臥位造影，常見橫膈膜周圍軟組織的衰減造成心允心壁缺損假影。國外文獻認為在再分佈相時加照俯臥位造影可有效幫助判別。本本研究為觀察東方人是否也有一樣的效果。
方法：24位無心肌梗塞病史及3位有陳舊性下壁梗塞病史之病人接受鉈-201心肌灌注掃描，踏步運動負荷採改良式布魯士踏步機方法，如受檢者無法自己運動，則使用dipyridamole靜脈注射。做完壓迫相檢查後4小時作一次再分佈相造影。分析後影像出現不可逆輕微缺損現象懷疑可能是軟組織衰減假影，於再分佈相取府臥位再造影一次。俯臥位影像處理後與壓迫相及再分佐相的仰臥位影像一起分析，鑑別心?下壁的活性是否有增加。
結果：俯臥位造影於24例無心肌梗塞病史病人中，21例(87.5%)有下壁活性增活，3例沒有活性增加(12.5%)。3例有下壁梗來病史之病人，其下壁活動均無增加。因此，加照府臥造影的確可幫助區別心肌下壁的不可逆輕徵缺損現象是否為軟組織衰減所照成的假影。
結論：使用未配置透射掃描的機器進行仰臥位鉈-201心肌灌注掃描時，如果心肌下壁出現不可逆輕微缺損影像，懷疑是軟組織的衰減所造成的假影，加作府臥位造影是很有幫助的。

Background: The supine position is the most commonly used position for 201T1myocardial SPECT. However, artifacts caused by diaphragmatic attenuation in the inferior wall are often noticed. The overseas studies showed the prone decubitus would minimize the effect of diaphragmatic attenuation. This study is aimed at the evaluation of this effect in the Oriental.
Methods: Twenty-four patients without and 3 patient with prior inferior myocardial infraction underwent stress 201T1 myocardial SPECT using either treadmill exercise or interavenous dipyridamole. Both the stress and 4-h redistribution images were acquired in the supine position. An additional acquisition in the prone position was performed if irreversible perfusion defect in the inferior wall was noticed.
Results: Using the prone position, increased tracer activity in the inferior wall was noticed in 21 (87.5%) of 24 patients without prior myocardial infarction. All 3 patients with prior infarction showed no increase in the inferior activity.
Conclusion: Using the scintillation camera system without transmission attenuation correction, an additional set of images taken in the prone position is useful in the differentiation of the artifact in the inferior wall caused by diaphragmatic attenuation.